Group 4 bent metallocenes and functional groups—Finding convenient pathways in a difficult terrain

Current approaches toward the development of functional group chemistry with sensitive Group 4 bent metallocenes are discussed. This includes polymerization reactions of functionalized olefins, electrophilic attack at the metallocene Cp-rings, the introduction of functional groups via fulvene routes, the reactions of pendant functional groups, including CH-activation reactions, Mannich-type carbon–carbon coupling reactions, olefin metathesis reactions and photochemical [2 + 2] cycloadditions. The formation of chelate–PR2-bridged metal–metal bonded early–late heterobimetallic bent metallocene derivatives is presented and some of their reactions are discussed.